A Deadly Inheritance ■ 149genetically engineered cells back into Felix’s
body. And the waiting began.
Klein published the early results in 2010.
After gene therapy, nine of the boys improved
with regard to bleeding and infections. They
were able to play soccer like their healthy peers,
they responded to vaccinations, and they did not
develop severe infectious diseases. Klein and his
colleagues showed that gene therapy for the fatal
WAS diagnosis is feasible, and that WAS can be
corrected.
A new therapy does not come without risks,
though. A few years after receiving the gene ther-
apy, seven of the patients developed leukemiaBolstered by these results, the scientists tested
the technique in human cells and finally, in
2005, began a human clinical trial in Germany.
The first two boys, both 3 years old, were admit-
ted in 2006. Between 2006 and 2009, 10 boys
were admitted to the clinical trial, with Felix
coming on board in 2009.
During the first phase of the trial, Felix had
to lie still for 9 hours as a machine pumped
blood out of his body in order to extract cells.
These cells were then taken to a laboratory
where scientists used a genetically modified
virus to insert a healthy copy of WA S into them
(Figure 8.14). The doctors then pumped the
(^5) The cells integrate
the new gene into
their genomes.
(^2) In the laboratory, a virus
is altered so that it is no
longer disease-causing.
(^1) Cells are removed
from the patient.
6
7
3
The genetically
altered cells are
injected back
into the patient.Thanks to the new
gene, these cells
now produce the
desired protein. A healthy copy of
the patient’s
missing or damaged
gene is inserted into
the virus.(^4) The virus is
mixed with the
patient cells.
Figure 8.14
Gene therapy
In gene therapy, genetic information is transferred into cells to achieve a desired effect. Gene therapy may be used to compensate
for a genetic mutation in a cell that causes the cell to malfunction. M
Q1: Which gene was missing or damaged in Felix’s case? From what chromosome would a healthy copy be taken?
Q2: Why did Dr. Klein’s group first conduct gene therapy on mice rather than on humans? What are the advantages and
limitations of this approach?
Q3: If Felix has children of his own someday, will they run the risk of inheriting his disorder, or has gene therapy removed
that possibility? Explain your reasoning.